The rapid downturn in the radio spectra could be related to thermal absorption due to an ionised medium along the line-of-sight to the hotspots, which we now investigate using the following free-free absorption model (e.g. [1]}),
\(S_{\nu } = S_{\nu _0} (\nu /\nu _0)^{\alpha _{\rm FFA}} \exp \left[ -\tau _{\rm \nu _0}\left( \nu / \nu _0 \right)^{-2.1} \right],\) 
